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Show 1901.] ANATOMY OF CHRYSOCHLORIS TREVELYANI. 29 The splenitis capitis, biventer cervicis, and complexus agree with Dobson's descriptions. The scalenus anticus (ventralis) rises from the transverse processes of the 5th and 6th cervical vertebras and is inserted into the first rib ventral to the subclavian artery and brachial plexus. There is no splenitis colli, and the so-called biventer cervicis, although it is quite a separate muscle from the complexus, is not at all biventral. The trachelo-mastoid is present and distinct. The rectus abdominis or rectus ventralis, as it would be more appropriate to. call it, agrees with Dobson's description in C. tre-velyani and 0. villosa. After the closest scrutiny I could detect no indications of lineaa transversa?. The external oblique rises from the 5th to the 17th ribs. The internal oblique is well developed and distiuct iu the posterior (caudal) portion of the abdomen, but is hardly marked at all in the anterior part. The transversalis in its attachments and direction of fibres agrees with Dobson's descriptions. Both the sterno-costalis and pyramidalis are absent. Muscles of the Fore Limb. The muscles of the pectoral region and shoulder agree with Dobson's description, with the following exceptions : - The teres major is a small muscle entirely unconnected with the latissimus dorsi. It has the usual attachments and it is evident that the muscle which Dobson calls teres major is really part of the triceps. The teres minor is absent, the origin of the middle head of the triceps is so great that there is no room for it. The muscle which Dobson describes as teres minor is really teres major. The latissimus dorsi agrees with Dobson's description, but there is a tendinous intersection in it opposite the elbow in one specimen, not in the other two. The levator scapulas and levator clavicuke are just as Dobson described them, but they are distinct at their insertion. I am inclined to regard them as a longitudinally split levator clavicidse or trachelo-acromial muscle, because this is the only mammal I have even seen with two muscles in this position. Elsewhere 1 I have stated m y reasons for regarding the trachelo-acromial muscle as a fixer of the scapula for the scapular head of the triceps to rise from, and it is probable that the extra size of that head in this animal is correlated with the double-fixing muscle. The supra- and infra-spinati have the usual attachments, but the former is much the larger of the two. The subscapularis is very thick, rising as it does from the deeply concave fossa. A great many of its fibres rise behind the axillary border from the front of the tendon of origin of the middle head of 1 '• Muscles of Mammals," Journal of Anatomy, vol. xxxii. p. 428. |